The present invention relates to a seat reclining apparatus for adjusting the reclining angle of a seat-back.
In the conventional seat reclining apparatus of the kind, a handle operated gear mechanism is used for adjusting the reclining angle as disclosed, for example, in Japanese Patent Publication No. Sho63(1988)-65325. The conventional seat reclining apparatus has an upper gear provided on the side of a seat-back frame, and a lower gear provided on the seat-cushion frame. The number of teeth of one of these two gears is at least one less than the number of teeth of the other. The two gears are meshed with each other and are supported on coaxial and eccentric portions of a shaft. The conventional seat reclining apparatus is so adapted that rotating the shaft makes it possible to recline the seat-back relative to the seat cushion. In order to retain the adjusted or reclined condition of the seat-back as it is, a washer is disposed in a frictional manner between the upper gear and the seat-cushion bracket.
However, the foregoing frictional force of the washer between the the outer gear and the seat-cushion bracket will prevent a smooth rotation of the shaft, which brings in that the reclining angle adjustment is cumbersome.